I got really lucky...I have a spotted mandarin male in my 57 rimless (20 long sump) who has taken to eating frozen food. He just went for it one day. He has plenty of pods too, and still roams around pecking at the rocks, but he's gotten pretty chunky and loves feeding time. I've had him for over a year and got him when the tank was about a year old. I also started with a little guy - my thought process (correct or not) was that a little one wouldn't eat as much. Heck, maybe the babies eat even more...either way, I'm really really happy he's thriving. Best of luck, they are truly beautiful fish!